1. Field of the Invention
The present invention relates to a blood-pressure monitoring apparatus which monitors the blood pressure of a living subject by periodically measuring a blood-pressure value of the subject.
2. Related Art Statement
There is known a blood-pressure ("BP") monitoring device which monitors the BP of a living subject, e.g., a patient, by periodically measuring a BP value of the subject. An example of the conventional BP monitoring device is disclosed in Japanese Patent Application laid open for public inspection under Publication No. 4(1992)-261640. The BP monitoring device includes a display device which displays each of the periodically measured BP values when each BP value is measured, or a graph representing a time-wise trend or change of the periodically measured BP values.
Even a patient whose BP needs to be monitored has a constant tendency or rate of change of his or her BP, in a short period of time. That is, in a short period, a patient's BP does not change irregularly. Hence, a BP monitoring device which displays a graph representing a time-wise trend of BP values periodically measured from a patient is employed by a doctor for predicting a future BP value of the patient. Even though the last or current BP value measured from the patient may not be abnormal, if the doctor can predict from the time-wise trend of the measured BP values that the patient's BP will be abnormal in future, the doctor can immediately give necessary treatments for the patient.
However, a doctor may not be able to check each of the BP values periodically measured from of a patient. Hence, there has been proposed a BP monitoring device of a type which generates an alarm sound, when judging that a measured BP value does not fall within a predetermined normal BP range, so that the doctor may be informed of the occurrence of an abnormality to the patient. However, so long as each measured BP value falls within the normal BP range, the conventional BP monitoring device does not take any actions, even in the case where a doctor would be able to predict that the patient's BP will be abnormal in future. Therefore, there are some cases where a long time passes before the BP monitoring device generates an alarm sound, after the patient's BP indicates its abnormality. Even in the case where the doctor can check each of the periodically measured BP values of the patient, the doctor may not be able to make an appropriate judgment.